MESA, Ariz. (AP) — President Donald Trump, seeking to frame the choices for voters in the midterm elections, said Friday that Democrats are “too extreme and too dangerous” to take control of Congress.

On a three-day swing out West to make his closing arguments for Republican candidates, Trump sought to hone in on immigration as one of the defining election issues this fall by falsely accusing Democrats of wanting “open borders” and encouraging illegal immigration.

Trump, trying to hold onto Republicans’ narrow 51-49 advantage in the Senate, said a vote for Sinema “is dangerous” because it would empower Senate Minority Leader Chuck Schumer and House Minority Leader Nancy Pelosi.

“The Democrat Party has become too extreme and too dangerous to be trusted with power,” he claimed.

Trump also had harsh words for Central American migrants trying to travel through Mexico and reach the U.S. border, declaring they aren’t “little angels” but “hardened criminals.”

Asked what evidence he had that they were “hardened criminals,” Trump told a reporter: “Oh, please. Please. Don’t be a baby.”

Thousands of the migrants have fled poverty and violence in their home countries. Others are in search of work and help for their families.

Trump also claimed without evidence that Democrats want them to enter the U.S. because “they’re gonna vote Democrat.”

Earlier Friday, during a roundtable at Luke Air Force Base, Trump said McSally, a former Air Force colonel and combat fighter pilot, is “brilliant and brave” and has a “very, very strange opponent.”

The two congresswomen are vying for the seat of Republican Sen. Jeff Flake, who is retiring. McSally was a Trump critic in 2016 and represents a Tucson district that voted for Democrat Hillary Clinton.

McSally has now embraced the president and hopes his visit to Arizona will unite Republicans against Sinema.

Trump campaigned Thursday in Montana on behalf of GOP Senate candidate Matt Rosendale and on Saturday will visit Elko, Nevada, to support Sen. Dean Heller, considered the most vulnerable Republican incumbent this fall.